I'm not sure that font choices are entirely subjective. Legibility matters, and it's not impossible that better legibility means fewer bugs and less eye/brain strain.

It would be cool if there was objective research into this. (I don't know of any, but I haven't tried searching very hard.)

I can't look at M+ without seeing M+. With other fonts - I'm old-fashioned and like Menlo, but I've tried many others - all I see is code.